Process for preparing detergent compositions having high bulk density

ABSTRACT

A method for producing detergent granules, includes the step of dry-neutralizing a liquid acid precursor of a non-soap, anionic surfactant with a water-soluble, solid, alkali inorganic substance. In this method, a dry-neutralizing step is carried out in the presence of 0.1 to 1.0 mol of an inorganic acid per mol of the liquid acid precursor of a non-soap, anionic surfactant. The above detergent granules have the features of extremely low tackiness of the granules and containing larger number of micropores. By using the detergent granules, a high-bulk density detergent composition having a small particle size can be obtained at high yields.

This application is the national phase under 35 U.S.C. §371 of prior PCTInternational Application No. PCT/JP97/03095 which has an Internationalfiling date of Sep. 3, 1997 which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to detergent granules comprising anon-soap, anionic surfactant and an inorganic salt. The presentinvention relates to a method for producing the above detergent granulesby a dry-neutralization process. The present invention further relatesto a high-bulk density detergent composition containing the abovedetergent granules.

BACKGROUND ART

In the detergent industries, recently, methods for producing powderdetergents having relatively high bulk densities are remarked. Suchpowdery detergents containing anionic surfactants, such asalkylbenzenesulfonates, are prepared in situ neutralization of an acidprecursor of the anionic surfactant with an alkali, such as sodiumhydroxide, sodium carbonate, or the like.

For instance, Japanese Patent Laid-Open No. 60-72999 and GB-2,166,452Bdisclose a process comprising the steps water of blending detergingaction components, a sulfonic acid and sodium carbonate, with water witha strong shearing device; cooling the resulting solid substances to 40°C. or lower; finely pulverizing the cooled product; and then forming thefine powders into granules. This method is a typical one of thoseconventionally proposed methods, in which the neutralization reactionproduct is a doughy mass, which necessitates a kneading device, such asa kneader, capable of supplying extremely large energy required for theneutralization reaction.

GB-1,369,269 discloses a method for producing an anionic detergentcomprising vigorously mixing deterging action components which are asulfonic acid and sodium carbonate powder by using a mixer equipped witha shearing device, such as Lödige PLOUGH SHARE Mixer. By this method, inorder to obtain products of particulate forms, not a doughy mass, it isnecessary to blow a gas stream into the two-component mixture mentionedabove, to thereby suitably make the reaction substances flowable andblend the reaction mixture. In order to carry out this treatment, themixer has to be made notably complicated. Also, since water serving toaccelerate the neutralization reaction is not added, the progress ofthis reaction is mild, so that relatively coarse products are formed.

Japanese Patent Laid-Open No. 3-33199 discloses a method of producing adetergent composition comprising the steps of dry-neutralizingcomponents in a high speed mixer/granulator at a temperature of 55° C.or less, and then adding a liquid binder thereto to carry outgranulation. Japanese Patent Laid-Open No. 4-363398 discloses a methodof producing a detergent composition comprising the steps ofdry-neutralizing components in a high speed mixer/granulator at atemperature of 55° C. or more, and then adding a liquid binder theretoto carry out granulation. Japanese Patent Laid-Open No. 3-146599discloses a method of producing a detergent composition comprising thesteps of dry-neutralizing components in a continuous high speed mixer;then increasing to a high bulk density using a moderate speed mixer; andthen cooling and/or drying the resulting product to carry outgranulation.

The detergent compositions obtainable by the methods described aboveinclude granules having small particle sizes. However, for practicalpurposes, the yield of the detergent composition comprising granules ofan even smaller particle size than those desired is yet to be improved.

Also, in the above methods, such factors in operating conditions as thepowder temperature, the water content, the powder blending efficiency,and the like, are optimally selected simply for the purpose of preparingdetergent compositions comprising granules having smaller particlesizes, never attempting to fundamentally improve the tackiness ascribedto the anionic surfactants, which causes agglomeration of the granulesand formation of coarse granules.

Japanese Unexamined Patent Publication No. 7-503750 discloses a methodof producing detergent granules comprising neutralizing an anionicsurfactant in an acid form with a granular neutralizing agent (sodiumcarbonate) of which has 50% by volume of particles of less than 5 μm indiameter in a high shearing mixer.

However, in this publication, no disclosures or suggestions concerningthe improvements of the yield of the detergent composition comprisinggranules having a desired particle size are made.

An object of the present invention is to provide detergent granules withsuppressed tackiness and small particle size.

Another object of the present invention is to provide a method forproducing the above detergent granules.

Still another object of the present invention is to provide a high-bulkdensity detergent composition comprising the above detergent granules.

These and other objects of the present invention will be apparent fromthe following description.

DISCLOSURE OF THE INVENTION

The present invention is concerned with the following:

-   (1) detergent granules comprising a non-soap, anionic surfactant and    an inorganic salt undetectable by X-ray diffraction method, wherein    the molar ratio of [inorganic salt undetectable by X-ray diffraction    method]/[non-soap, anionic surfactant] is from 0.1 to 1.0;-   (2) the detergent granules described in item (1) above, wherein the    non-soap, anionic surfactant is contained in the detergent granules    in an amount of 28% by weight or more and less than 50% by weight;-   (3) the detergent granules described in item (1) above, wherein the    non-soap, anionic surfactant is contained in the detergent granules    in an amount of 10% by weight or more and less than 28% by weight,    and wherein the molar ratio of [inorganic salt undetectable by X-ray    diffraction method]/[non-soap, anionic surfactant] is from 0.3 to    1.0;-   (4) a method for producing detergent granules, comprising the step    of dry-neutralizing a liquid acid precursor of a non-soap, anionic    surfactant with a water-soluble, solid, alkali inorganic substance,    wherein a dry-neutralizing step is carried out in the presence of    0.1 to 1.0 mol of an inorganic acid per mol of the liquid acid    precursor of a non-soap, anionic surfactant;-   (5) the method described in item (4) above, further comprising the    step of adding a free-flowing aid after the dry-neutralizing step,    to surface-modify the detergent granules;-   (6) the method described in item (4) above, further comprising the    step of adding a liquid component after the dry-neutralizing step;-   (7) the method described in item (6) above, further comprising the    step of adding a free-flowing aid after the step of adding a liquid    component, to surface-modify the detergent granules;-   (8) the method described in any one of items (4) to (7) above,    wherein the liquid acid precursor of a non-soap, anionic surfactant    is a linear alkylbenzenesulfonic acid obtained by SO₃ gas    sulfonation method;-   (9) the method described in any one of items (4) to (8) above,    wherein an amount of an inorganic acid preexisting in the liquid    acid precursor of a non-soap, anionic surfactant is 0.09 mol or less    per mol of the liquid acid precursor;-   (10) the method described in any one of items (4) to (9) above,    wherein the inorganic acid is sulfuric acid or phosphoric acid;-   (11) the method described in any one of items (4) to (10) above,    wherein the resulting detergent granules contain the non-soap,    anionic surfactant in an amount of 28% by weight or more and less    than 50% by weight, and have a molar ratio of [inorganic salt    undetectable by X-ray diffraction method]/[non-soap, anionic    surfactant] of from 0.1 to 1.0;-   (12) the method described in any one of items (4) to (10) above,    wherein the resulting detergent granules contain the non-soap,    anionic surfactant in an amount of 10% by weight or more and less    than 28% by weight in the detergent granules, and have a molar ratio    of [inorganic salt undetectable by X-ray diffraction    method]/[non-soap, anionic surfactant] of from 0.3 to 1.0; and-   (13) a high-bulk density detergent composition having a bulk density    of 500 g/L or more, comprising the detergent granules according to    any one of items (1) to (3) above, or the detergent granules    obtainable by the method of any one of items (4) to (12).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing X-ray diffraction patterns of the detergentgranules obtained in Comparative Example 13. Its measurement is taken byX-ray diffraction analyzer “RAD-RC” (manufactured by Rigaku Co., Ltd.).In the figure, the arrows indicate the diffraction peaks of the powderysodium sulfate.

FIG. 2 is a graph showing X-ray diffraction patterns of the powderysodium sulfate.

FIG. 3 is a graph showing the relationship between the amount of thesodium sulfate added as the starting material in the preparation of thedetergent compositions and the peak intensity at d=2.78 in the X-raydiffraction analysis. This graph can be used as a calibration curve fordetermining the “powdery sodium sulfate” added as the starting materialcontained, in the detergent composition from the peak intensity obtainedby X-ray diffraction analysis of the detergent composition.

FIG. 4 is a graph showing X-ray diffraction patterns of the detergentcomposition obtained in Example 12. In the figure, the arrows indicatethe diffraction peaks of the powdery sodium sulfate.

FIG. 5 is a graph showing the relationship between the entire amount ofthe sodium sulfate in the detergent composition theoretically calculatedfrom the starting material composition and the amount of sodium sulfatein the detergent composition quantified by ion chromatography. The graphis prepared by the chemically determined amounts of sodium sulfate inthe detergent compositions of Examples 11, 12, 13, 16, 17, 18, and 21and Comparative Examples 11, 16, and 19. This graph can be used as acalibration curve for obtaining the “entire amount of sodium sulfate”contained in the detergent composition.

FIG. 6 is a graph showing the relationship between the depths from thesurface of the granules of the detergent compositions and the relativeintensity of the peaks ascribed to sodium sulfate, an inorganic salt(namely, the ratio between the peak intensity of sodium sulfate and thepeak intensity of the LAS-Na), as determined by FT-IR/PAS analysis ofthe detergent compositions obtained in Example 11 and in ComparativeExample 11. Here, bold line represents data of Example 11, and solidline represents data of Comparative Example 11.

FIG. 7 is a graph showing the relationship of the microporous diameterand the microporous capacity of the detergent compositions obtained inExample 18 and in Comparative Example 16. Here, bold line representsdata of Example 18, and solid line represents data of ComparativeExample 16.

BEST MODE FOR CARRYING OUT THE INVENTION

The method for producing detergent granules of the present inventioncomprises the step of dry-neutralizing a liquid acid precursor of anon-soap, anionic surfactant with a water-soluble, solid, alkaliinorganic substance, wherein a dry-neutralizing step is carried out inthe presence of 0.1 to 1.0 mol of an inorganic acid per mol of theliquid acid precursor of a non-soap, anionic surfactant.

In the present invention, it is possible to produce detergent granulesand high-bulk density detergent composition by the above method. Inother words, since the granules, which are obtainable by the step ofdry-neutralizing a liquid acid precursor of the non-soap, anionicsurfactant with a water-soluble, solid, alkali inorganic substance inthe intentional presence of an inorganic acid, comprise neutralizedsalts derived from the inorganic acids in relatively larger amounts atnear the surfaces of the granules than at the inner portion of thegranules, the resulting granules have low tackiness and small particlesizes. Also, since the tackiness of the granules can be suppressed, thegranules with a high surfactant content can be obtained without causingagglomeration of the granules.

The embodiments of the dry-neutralization process in the method of thepresent invention are not particularly limited as long as thedry-neutralization process is carried out in the presence of a givenamount of an inorganic acid. An embodiment includes, for instance,carrying out the dry-neutralization process comprising blending amixture of a liquid acid precursor of a non-soap, anionic surfactant andan inorganic acid with a water-soluble, solid, alkali inorganicsubstance. The present invention will be further explained in detailbelow by taking the above embodiment as one example of the method of thepresent invention.

This embodiment comprises 1) a blending step and 2) a dry-neutralizingstep. Each of the steps will be detailed below.

1) Blending Step

This process precedes the dry-neutralizing step and comprises blending aliquid acid precursor of a non-soap, anionic surfactant with aninorganic acid in advance.

The liquid acid precursors of non-soap, anionic surfactants refer to theprecursors of the non-soap, anionic surfactants in the form of acids ina liquid state, which are formed into salts by neutralization reaction.Therefore, the liquid acid precursors of non-soap, anionic surfactantsmay be precursors having the above properties of any of known anionicsurfactants acids without particular limitations. Concrete examplesthereof include linear alkylbenzenesulfonic acids (LAS), α-olefinsulfonic acids (AOS), alkyl sulfuric acids (AS), and internal olefinsulfonic acids, sulfonic acids of fatty acid esters, alkylether sulfuricacids, dialkyl sulfosuccinic acids, and the like. The liquid acidprecursors may be used singly or in a combination of two or morecomponents.

The preferred inorganic acids usable in the present invention includesulfuric acid and phosphoric-acid. More preferred inorganic acidincludes sulfuric acid. Also, there are some cases where remainingsulfuric acid is contained in the liquid acid precursor of a non-soap,anionic surfactant usable in the present invention by the productionprocess of the liquid acid precursor.

The linear alkylbenzenesulfonates listed as the preferred liquid acidprecursors of a non-soap, anionic surfactant may be prepared by one ofthe following two typical methods.

-   -   (1) Oleum sulfonation method.    -   (2) SO₃ gas sulfonation method.    -   (1) is a classical method for producing linear        alkylbenzenesulfonic acids, wherein sulfuric acid may be        contained in the resulting product in an amount of about 0.3 mol        per mol of the linear alkylbenzenesulfonic acid. Also, in (2),        the purity of the linear alkylbenzenesulfonic acids in the        resulting product is high, and the amount of remaining sulfuric        acid is relatively low, wherein the amount of remaining sulfuric        acid is usually 0.2 mol or less per mol of the linear        alkylbenzenesulfonic acid. Presently, from the aspects of        quality and productivity, the method (2) is mainly employed as        the method of giving high-purity linear alkylbenzenesulfonic        acids. In the present invention, the linear        alkylbenzenesulfonates prepared by (2) are preferably used.

As mentioned above, the inorganic acid may preexist in the precursors ofnon-soap, anionic surfactants in some cases. The amount of the inorganicacid, namely the amount of the inorganic acid preexisting in the liquidacid precursors of the non-soap, anionic surfactants, is notparticularly limited. From the viewpoint of the hue in the resultingdetergent granules, the amount of the inorganic acid is preferably 0.09mol or less, more preferably 0.06 mol or less, per mol of the liquidacid precursor.

The amount of the inorganic acid in the method of the present inventionis from 0.1 to 1.0 mol per mol of the liquid acid precursor of anon-soap, anionic surfactant, preferably from 0.1 to 0.8 mol, morepreferably from 0.15 to 0.65 mol, still more preferably from 0.2 to 0.6mol, still more preferably from 0.25 to 0.55 mol, per mol of the liquidacid precursor. From the viewpoint of inhibiting the formation of coarsegranules of the detergent granules, the amount of the inorganic acid ispreferably 0.1 mol or more, and from the viewpoint of securing thecompositional freedom of the concentrated detergent, the amount of theinorganic acid is preferably 1.0 mol or less. In particular, from theviewpoint of the microporosity of the detergent granules as detailedbelow, the amount of the inorganic acid is preferably 0.3 mol or more,more preferably from 0.3 to 1.0 mol, still more preferably from 0.3 to0.8 mol, still more preferably 0.35 to 0.7 mol, per mol of theprecursor.

Also, as clearly described in Examples set forth below, by changing theratios between the liquid acid precursor of a non-soap, anionicsurfactant and the inorganic acid, the tackiness and/or microporosity ofthe resulting neutralized granules can be varied.

Therefore, the above ratio can be appropriately selected and adjusted bycontents of the non-soap, anionic surfactant in the granules, kinds ofinorganic acids used, differences in the additives employed, or thelike.

In other words, it is desired that the inorganic acid is added to thestarting material components, including the liquid acid precursor of anon-soap, anionic surfactant, in the case where the amount of theinorganic acid preexisting in the liquid acid precursor of a non-soap,anionic surfactant is not in the above range; or alternatively in thecase where the tackiness and/or the microporosity of the granules is tobe increased, even when the amount of the inorganic acid preexisting inthe liquid acid precursor is in the above range; or the case where theneutralized granules are to be made even smaller.

The mixers usable in this step are not particularly limited. Concreteexamples thereof include mixing vessel for liquid components equippedwith an agitating device. Also, the mixing may be carried out to anextent such that each of the components is uniformly mixed.

2) Dry-Neutralizing Step

This step comprises adding a mixture of the liquid acid precursor of anon-soap, anionic surfactant and an inorganic acid obtained in theprevious step to a water-soluble, solid, alkali inorganic substance, todry-neutralize of the liquid acid precursor of a non-soap, anionicsurfactant. Incidentally, in this step, by adding the liquid acidprecursor of a non-soap, anionic surfactant and an inorganic acid, theneutralization reaction and the granulation process concurrently takeplace, to form the neutralized granules.

Concretely, this dry-neutralizing step includes the following steps:

-   -   (a) blending a water-soluble, solid, alkali inorganic substances        and/or a known substance generally employed in detergent        compositions, wherein the water-soluble, solid, alkali inorganic        substance is used in an amount of equal to or greater than that        necessary for neutralizing a mixture (amount for neutralization)        comprising a liquid acid precursor of a non-soap, anionic        surfactant and an inorganic acid in the mixture obtained in the        blending step described above; and    -   (b) adding the mixture comprising the liquid acid precursor of a        non-soap, anionic surfactant and the inorganic acid obtained in        the above blending step to the mixture obtainable in step        -   (a) to neutralize the mixture obtained in step        -   (a) while the mixture remains in a particulate form.            Step (a)

The water-soluble, solid, alkali inorganic substances include any oneusually usable as alkalizing agents in detergent compositions. Concreteexamples thereof include sodium carbonate, sodium hydrogencarbonate,sodium silicate, potassium carbonate, calcium carbonate, and the like,which may be used alone or in combination. Among the water-soluble,solid, alkali inorganic substances, sodium carbonate can be used as apreferred embodiment because the sodium carbonate can act as a detergentbuilder and an alkalizing agent in the final detergent composition.Therefore, by adding and blending the water-soluble, solid, alkaliinorganic substance components in this step, in amounts sufficient toneutralize a mixture of the liquid acid precursor and the inorganic acidin addition to the amount of sodium carbonate acting as builders andalkalizing agents mentioned above, the neutralization reaction can befavorably carried out.

Specifically, it is preferred that the water-soluble, solid, alkaliinorganic substances is added in an amount of equal to or greater thanthat for neutralization of the liquid acid precursor of a non-soap,anionic surfactant and the inorganic acid (amount for neutralization),for example, preferably 1 to 20 times, more preferably 2 to 10 times,particularly 3 to 8 times, the amount for neutralization.

Also, the average particle size of the water-soluble, solid, alkaliinorganic substance is not particularly limited. From the viewpoint offurther increase in yield and storage stability, the average particlesize is preferably 30 μm or more, more preferably from 40 to 200 μm,particularly from 50 to 100 μm. Here, the average particle size of thewater-soluble, solid, alkali inorganic substance is calculated based onvolume and measured with a laser diffraction particle size distributionanalyzer (“LA-500,” manufactured by HORIBA Ltd.).

Further, in the present invention, any of the known substances generallyemployed in detergent compositions may be also blended. Concreteexamples thereof include tripolyphosphates; crystalline or amorphousalkali metal aluminosilicates; crystalline silicates; fluorescers;pigments; anti-redeposition agents, such as polycarboxylate polymers andsodium salt of carboxymethyl cellulose; granular surfactants, such asfatty acids, salts thereof, linear alkylbenzenesulfonates, and alkylsulfates; spray-dried powders, diatomaceous earth, calcite, kaolin,bentonite, sodium sulfate, sodium sulfite, and the like. The abovesubstances may be optionally used depending upon the application of thegranules. When these substances are added, it is desired that they areused as a mixture with the water-soluble, solid, alkali inorganicsubstance.

In the case where the detergent compositions comprising thetripolyphosphates as main builder components are prepared, the averageparticle size of the tripolyphosphates is not particularly limited, andthe average particle size may be preferably from 1 to 3.0 μm, morepreferably from 5 to 20 μm, still more preferably from 6 to 15 μm. Fromthe viewpoint of inhibition of the agglomeration of the detergentgranules, smaller the average particle size of the tripolyphosphate,higher the yields. On the other hand, from the viewpoint of productivityfor preparing the detergent granules with small particle sizes in anindustrial scale, the average particle size of the tripolyphosphates ispreferably 1 μm or more. From the viewpoint of inhibiting theagglomeration of the detergent granules, the average particle size ispreferably 30 μm or less. Here, in the present specification, theaverage particle size of the tripolyphosphate is calculated based onvolume and measured with a laser diffraction particle size distributionanalyzer (“LA-500,” manufactured by HORIBA Ltd.).

When the tripolyphosphate is added, the amount of the tripolyphosphateis not particularly limited. When the detergent granules of the presentinvention per se are used as the detergent composition, or when thedetergent granules of the present invention are included as aconstituting element of a different detergent composition, thetripolyphosphate is preferably contained in the final granular productin an amount of 2 to 50% by weight, more preferably from 10 to 40% byweight, particularly preferably from 15 to 35% by weight. From theviewpoint of inhibiting the agglomeration of the neutralized granularmixture, the amount of the tripolyphosphate is preferably 2% by weightor more. From the viewpoint of securing the compositional freedom of theresulting detergent composition, the amount is preferably 50% by weightor less.

Further, in cases where detergent compositions having the alkali metalaluminosilicates as main builder components are prepared, an excessagglomeration can be inhibited by the addition of the alkali metalaluminosilicates in this step. Moreover, the alkali metalaluminosilicate also acts as an aid for disintegrating the agglomeratedproduct with the chopper of the agitation granulator. The alkali metalaluminosilicates have an average particle size of from 1 to 30 μm.

Here, the average particle size of the aluminosilicate is calculatedbased on volume and measured with a laser diffraction particle sizedistribution analyzer (“LA-500,” manufactured by HORIBA Ltd.).

Also, the amounts of fluorescers, pigments, anti-redeposition agents,granular surfactants, spray-dried powders, diatomaceous earth, calcite,kaolin, bentonite, sodium sulfate, sodium sulfite, and the like are notparticularly limited.

The mixers usable in step (a) for blending each of the above componentsare not particularly limited, and an agitation granulator may besuitably used. The agitation granulators are not particularly limited,and it is preferred that the agitation granulators are equipped withagitation blades and a chopper for disintegration and dispersion (orwith a functionally equivalent means).

Concrete examples of the agitation granulators usable in the presentinvention for a batch process include Vertical Granulator (manufacturedby Powrex Corp.); High-Speed Mixer (manufactured by Fukae Powtec KogyoCorp.); Lödige Mixer (manufactured by Matsubo Co., Ltd.); PLOUGH SHAREMixer (manufactured by PACIFIC MACHINERY & ENGINEERING Co., LTD.);Gericke Mixer (manufactured by Meiji Machine Co., Ltd.), and the like.Here, particular preference is given to the Lödige Mixer and the PLOUGHSHARE Mixer. Concrete examples of the agitation granulators usable for acontinuous process include continuous Lödige Mixer (moderate speedmixer: those having relatively long residence time); CB recycler(manufactured by Lödige) as a high-speed mixer (having relatively shortresidence time); Turbilizer (manufactured by Hosokawa MicronCorporation); Shugi Mixer (manufactured by Powrex Corp.); Flow Jet Mixer(manufactured by Funken Powtechs, Inc.), and the like. Incidentally, inthe present invention, the above mixers may be suitably used incombination.

Also, it is more preferred that the agitation granulators are equippedwith a jacket for adjusting the internal temperature of the granulatorand a nozzle for blowing a gas into the agitation granulator.

The extent of mixing in step (a) is not particularly limited, and mixingmay be preferably carried out to an extent such that each of thecomponents is uniformly mixed. For instance, in the case where theagitation granulators are used in this step, the operating conditions ofthe agitation granulators may be, for example, preferably a blendingtime of within five minutes. The agitating speed of the main shaft andthe chopper speed for disintegration and dispersion may be suitably setdepending on the kinds of the mixers used. For instance, in the case ofmixers for a batch process, the peripheral agitating speed of the mainshaft is preferably from 2 to 15 m/s, and the peripheral chopper speedfor disintegration and dispersion is preferably from 20 to 60 m/s.

Incidentally, during blending, or at the completion of blending in step(a), water may be added as a reaction initiating agent. By adding thereaction initiating agent, the neutralization reaction can be favorablyaccelerated. The amount of water added is not particularly limited, andthe amount of water is preferably from 0.2 to 3 parts by weight, morepreferably from 0.5 to 1.5 parts by weight, based on 100 parts by weightof the powdery mixture in step (a). From the viewpoint of initiating theneutralization reaction, the amount of water is preferably 0.2 parts byweight or more, and from the viewpoint of inhibiting the agglomerationof the detergent granules, the amount is preferably 3 parts by weight orless. Incidentally, in cases where the above components, such as theliquid acid precursor of a non-soap, anionic surfactant, contain water,or in cases where other aqueous starting material solutions are used, orin cases where water-containing powdery starting materials are used, theamount of water to be added may be determined by considering the watercontents of these components.

In addition, as still more preferred reaction initiating agents, anaqueous solution of alkalis may be added. By using an aqueous solutionof alkalis as a reaction initiating agent, when compared with water, notonly the neutralization reaction can be further accelerated, but alsothe particle size of the resulting detergent granules can be made smalland thus the bulk density can be made large.

The amount of the aqueous solution of alkalis is preferably from 0.05 to0.5 times the amount, more preferably from 0.10 to 0.45 times theamount, particularly preferably from 0.15 to 0.40 times the amount, forneutralizing the liquid acid precursor of a non-soap, anionicsurfactant. From the viewpoint of initiating the neutralization reactionto obtain desired effects, the amount of the aqueous solution of alkalisis preferably equal to or greater than 0.05 times the amount forneutralization, and from the viewpoint of inhibiting the agglomerationof the detergent granules, the amount is preferably equal to or lessthan 0.5 times the amount for neutralization. Incidentally, although theconcentration of the aqueous solution of alkalis is not particularlylimited, in cases of low concentrations, excess amount of water issupplied to the mixture along with the given amount of the aqueoussolution of alkalis, so that the agglomeration of the detergent granulesis liable to take place. Therefore, the concentration of the aqueoussolution of alkalis is preferably from 20 to 50% by weight, morepreferably 30 to 50% by weight, particularly preferably from 40 to 50%by weight.

Also, the kinds of the aqueous solutions of alkalis usable in thepresent invention are not particularly limited. Examples thereof includeaqueous sodium hydroxide, aqueous potassium hydroxide, and the like,which are aqueous solutions of strong-alkalis which easily causeneutralization reaction with the liquid acid precursors of the non-soap,anionic surfactants. Among them, the aqueous sodium hydroxide issuitably used from the viewpoint of costs. Also, it is more preferredthat the aqueous solutions of alkalis mentioned above have a pH of 12 ormore.

In addition, mixing in this step may be preferably carried out to anextent such that the added aqueous solution of alkalis is uniformlydispersed.

Step (b)

In step (b), in order to carry out the dry-neutralization process of theliquid acid precursor of a non-soap, anionic surfactant, the liquid acidprecursor or a mixture of the liquid acid precursor and the inorganicacid may be gradually added to the water-soluble, solid alkali inorganicsubstance. The time required for the addition of the liquid acidprecursor or the above mixture depends upon the amount of the liquidacid precursor or the above mixture added and thus cannot begeneralized. In the case of employing mixing in a batch process, thetime required is generally one minute or more, more preferably from 1 to10 minutes, still more preferably 2 to 7 minutes. Here, when the liquidacid precursor or the above mixture is added in an extremely short time,the liquid acids remaining unreacted accumulate, thereby making itlikely to cause excess agglomeration. Therefore, it is preferred thatthe liquid acid precursor or the above mixture is added in one minute orlonger.

Also, the liquid acid precursor or the above mixture may be addedcontinuously or added separately in plural portions. Also, a pluralityof addition means may be provided.

Incidentally, the mixers usable in step (b) are not particularlylimited, with a preference given to the agitation granulatorsexemplified in step (a).

After the addition of the liquid acid precursor or the above mixture, itis desired that the agitation granulator is operated for additional 30seconds or more, more preferably one minute or more. By having thisstep, the neutralization reaction and the granulation process can befavorably completed.

In step (b), it is preferred that the neutralization is carried outwhile blowing a gas into an agitation granulator. This is because theexcess water produced in the neutralization reaction can be evaporatedand the granular product can be cooled with the gas, to thereby inhibitthe granular product from forming into a doughy mass. The gas includesan N₂ gas, air, and the like. The amount of gas blown (amount of gasflow) is not particularly limited. The gas is blown at a rate ofpreferably equal to or greater than 0.002 parts by weight per minute,more preferably equal to or greater than 0.02 parts by weight perminute, based on 100 parts by weight of the granular product.

By carrying out the above processes, the dry-neutralization process iscompleted.

The detergent granules obtainable by the method of the present inventiondescribed above may be further subjected to surface modification. Inother words, the method for producing the detergent granules of thepresent invention may further comprise the step of adding a free-flowingaid to the detergent granules obtained after the dry-neutralizing step,to surface-modify the detergent granules. By surface-modifying thedetergent granules, since further improvements in the free-flowabilityand the storage stability of the resulting detergent granules can beattained, the surface-modifying step is suitably provided, for instance,in a case where the detergent granules of the present invention areincluded as one constituting element of the detergent composition. Thesurface modification can be carried out by adding a surface modifier asa free-flowing aid while blending the detergent granules in an agitationgranulator (surface-modifying step).

The surface modifiers may be any of conventionally known ones, andcrystalline or amorphous alkali metal aluminosilicates (zeolite),calcite, diatomaceous earth, silica, and the like may be suitably used.The above aluminosilicates more preferably have an average particle sizeof 10 μm or less. Also, the amount of the surface modifiers in thedetergent composition, which is the final product, is preferably from 2to 15% by weight, more preferably from 4 to 12% by weight. Incidentally,the average particle size of the surface modifier is calculated based onvolume and measured with a laser diffraction particle size distributionanalyzer (“LA-500,” manufactured by HORIBA Ltd.).

Also, the operating time of the agitation granulator in cases where thesurface modifiers are added is not particularly limited, and theoperating time may be preferably from 1 to 5 minutes.

Incidentally, in the method of the present invention, the optionalliquid components may be added depending upon the composition of thedetergent compositions to be obtained (step of adding liquidcomponents). The addition of the liquid components may be carried out atany stage without particular limitation. For instance, the addition ofthe liquid components may be carried out prior to or during the processof the dry-neutralization, or the addition may be alternatively carriedout after the dry-neutralization. It is preferred that the addition iscarried out prior to the addition of the surface modifiers. However, incertain cases where the detergent granules obtained after the step ofadding the liquid components have excellent free-flowability and/orexcellent storage stability, it is unnecessary to add the surfacemodifier as a free-flowing aid.

Examples of the liquid components include any optional liquid componentsin detergent compositions, including nonionic surfactants; water-solublepolymers, such as polyethylene glycol, acrylic acid-maleic acidcopolymers, and the like; fatty acids, and the like. The liquidcomponents may be used singly or a combination of two or more kinds.From the viewpoint of inhibiting the agglomeration of the detergentcomposition, the amount of the liquid components may be preferably 15%by weight or less, more preferably 10% by weight or less, of thedetergent composition, which is the final product.

Further, in the present invention, any of the following known substancesgenerally employed in detergent compositions may be also blended to thedetergent granules obtained after the dry-neutralizing step. Forinstance, these substances may be added prior to the step of addingliquid components and/or prior to the surface-modifying step. Examplesof these substances include tripolyphosphates, crystalline or amorphousalkali metal aluminosilicates, crystalline silicates, fluorescers,pigments, anti-redeposition agents such as polycarboxylate polymers andsodium salt of carboxymethyl cellulose, granular surfactants such asfatty acids, salts thereof, linear alkylbenzenesulfonates and alkylsulfates, spray-dried powders, diatomaceous earth, calcite, kaolin,bentonite, sodium sulfate, sodium sulfite, and the like. The abovesubstances can be optionally used depending upon the applicationsthereof.

Also, the operating time of the agitation granulator in cases where theaddition of the liquid components is carried out prior to the additionof the surface modifiers is not particularly limited, and the operatingtime may be preferably from 0.5 to 8 minutes.

Specifically, there are the following embodiments as preferredembodiments for the methods for producing the detergent granules of thepresent invention:

-   [1] an embodiment further comprising the step of adding a liquid    component after the dry-neutralizing step; and-   [2] an embodiment further comprising the step of adding a    free-flowing aid after the step of adding a liquid component in    embodiment [1], to surface-modify the detergent granules.

The hue of the surface-modified, detergent granules obtained by themethod described above is not particularly limited. For instance, in thecase where the particle size of the surface-modified, detergent granulesis evenly sized at 350 to 500 μm and the above detergent granules isanalyzed by photoelectric calorimeter, the Hunter Lab coloration isdesirably 90 or more in its L value.

In the present invention, the following optional components may befurther added to the detergent composition. The optional componentsinclude, for instance, enzymes, perfumes, bleaching agents, pigments,and the like. Such optional components may be formulated by blending thedetergent granules obtainable by the method of the present inventionwith the above components using mixers, such as a rotary mixer.

Modes for carrying out the present invention are not limited to theabove methods. In other words, the present invention is applicable forthe methods for producing known powdery detergent compositions havinghigh bulk density and for methods for producing the commercial productsthereof, the high-bulk density detergent compositions being obtained bythe dry-neutralization process of the liquid acid precursor of ananionic surfactant.

In general, the particle size of the detergent granules obtained by thedry-neutralization process increases as the proportion of the non-soap,anionic surfactant increases. Also, similarly, the particle size tendsto increase as the proportions of the other liquid starting materials,such as nonionic surfactants and polymer solutions, increase. Forinstance, among the granules obtainable by the dry-neutralizationprocess having extremely high proportion of the anionic surfactant, inthe case where the proportion of the granules having suitably smallparticle size is low, the granules of the desired particle size rangecan be obtained at high yields by pulverizing an entire amount of theobtained neutralized granules in the presence of a pulverizing aid, andthen classifying the granules. Also, when the proportions of the otherliquid starting materials, such as nonionic surfactants and polymersolutions, are increased, the granules having suitably small particlesize can be obtained at high yields.

Also, the detergent granules obtainable by the method of the presentinvention may be used as a constituting element of a different detergentcomposition.

In addition, in the present invention, blending may be carried out bysupplying each of the liquid acid precursor of a non-soap, anionicsurfactant, the water-soluble, solid alkali inorganic substance, and theinorganic acid at once. In this case, the blending process and theneutralization and granulation process are concurrently carried out.This embodiment is highly preferable for the method in a continuousprocess.

The detergent granules of the present invention thus obtained comprise anon-soap, anionic surfactant and an inorganic salt undetectable by X-raydiffraction method, wherein the molar ratio of [inorganic saltundetectable by X-ray diffraction method]/[non-soap, anionic surfactant]is from 0.1 to 1.0.

The biggest feature of the detergent granules of the present inventionis in that the above inorganic salt is undetectable by X-ray diffractionmethod. Here, the phrase “undetectable by X-ray diffraction method”means that the material does not have a definite diffraction peak in theanalysis of the sample by X-ray diffraction method, and that theidentification of peaks cannot be made even when using any ofdiffraction patterns reported, for instance, in JCPDS (Joint Committeeon Powder Diffraction Standards). Incidentally, in X-ray diffractionpatterns, in certain cases, no definite diffraction peaks but indefinitediffraction halo patterns May be observed. However, even in such casesit cannot be said to be detectable by X-ray diffraction method. Typicalexamples of the inorganic salts include sodium sulfate (Glauber's salt).

For instance, since the detergent granules of Comparative Example 13,which is produced without using the method of the present invention,contain powdery sodium sulfate (Na₂SO₄), diffraction peaks shown in FIG.1 are detectable in X-ray diffraction patterns of the granules. Thesepeaks are identified as sodium sulfate, for instance, by No. 37-1465 ofJCPDS (FIG. 2). Also, as shown in FIG. 3, the amount of the powderysodium sulfate can be quantified by preparing a calibration curve of thepowdery sodium sulfate and the X-ray peak intensities using the X-raydiffraction peaks. By contrast, as typically exemplified by Example 12,in the granules of the present invention, diffraction peaks ascribed toany of the diffraction patterns of sodium sulfate are undetectable byX-ray diffraction method (FIG. 4), even though sodium sulfate can bechemically quantified by the method described below, thereby making itimpossible to identify the sodium sulfate by X-ray diffraction method.

On the other hand, the content of the inorganic salt in the detergentgranules can be chemically quantified, for instance, by analyzing means,such as ion chromatography. For example, in a case where the inorganicsalt is a sulfate, it is possible to quantify the sulfate contained inthe detergent granules by using a calibration curve of sulfate ionsprepared in advance. Similarly in the detergent granules of the presentinvention, the sulfate contained in the granules can be quantified asshown in FIG. 5. Also, the non-soap, anionic surfactant can bequantified, for instance, by carrying out qualitative and quantitativemethods in a synthetic detergent testing method (according to JIS K3362)for the anionic surfactants.

In the case where inorganic salts, such as powdery sodium sulfate andpowdery sodium phosphate, obtained by the process other than thedry-neutralization process in the method of the present invention, arenot used at all as the starting materials, since the inorganic salts,such as sodium sulfate and sodium phosphate, contained in the detergentgranules and formed by the method of the present invention areundetectable by X-ray diffraction method, the amount of the inorganicsalts chemically quantified would be considered to be the same as “theamount of the inorganic salt undetectable by X-ray diffraction method.”Therefore, the molar ratio of [inorganic salt undetectable by X-raydiffraction method]/[non-soap, anionic surfactant] can be calculatedfrom the amount of the inorganic salts and the amount of the non-soap,anionic surfactant quantified by the methods described above.Incidentally, even in cases where, for instance, the powdery sodiumsulfate mentioned above and the detergent granules of the presentinvention are mixed to give a desired detergent composition, the amountof the inorganic salt undetectable by X-ray diffraction method can becalculated by the difference in the amounts of sodium sulfate as shownin FIG. 5 and FIG. 3, and the above molar ratio can be calculated fromthis value.

The detergent granules of the present invention comprise a non-soap,anionic surfactant and an inorganic salt undetectable by X-raydiffraction method, wherein the molar ratio of [inorganic saltundetectable by X-ray diffraction method]/[non-soap, anionic surfactant]is from 0.1 to 1.0. From the viewpoint of suppressing the tackiness ofthe granules, the molar ratio is preferably 0.1 or more, and from theviewpoint of securing the compositional freedom of the detergentcomposition, the molar ratio is preferably 1.0 or less.

The detergent granules of the present invention mentioned above have theproperties of (1) having extremely low tackiness of the granules, and(2) having a large number of micropores. The detailed properties of thegranules of the present invention will be described hereinbelow.

(1) Low Tackiness

The present inventors have found that the detergent granules of thepresent invention show extremely low tackiness of the granules, and thatthis tackiness is dependent upon the molar ratio of the inorganic saltto the non-soap, anionic surfactant, wherein larger the molar ratio ofthe inorganic salt, lower the tackiness of the granules.

Here, the tackiness of the granules can be evaluated by a fracture loadof the compression molding product of the granules as detailed below. Acylinder having 40 mm in diameter is uniformly charged with a 40 gsample, and a 1 kg load is applied with a piston, and the piston-chargedcylinder is allowed to stand for three minutes, to thereby mold thegranules into cylindrical shapes. The molded samples are taken out ofthe cylinder. Thereafter, a force required for breaking the moldedsample is measured by using a rheometer (manufactured by FudohkogyoK.K.), and this force is defined as the fracture load. In general,smaller the value of the fracture load, smaller the tackiness of thegranules and less the agglomeration being caused thereby. The fractureload varies depending upon the amounts formulated, and the values of thefracture load of the detergent granules of the present invention arelower than those of the granules with the same compositions to thepresent invention except for the amount of the inorganic salt used inthe method of the present invention, so that improvements in thetackiness of the granules in the detergent granules of the presentinvention can be confirmed.

The present inventors have found that the detergent granules obtained bythe method of the present invention comprise a composite layercontaining the inorganic salt and the non-soap, anionic surfactant inthe surface layer of the granules. Also, they have found that since theinorganic salts are present in relatively larger amounts at near thesurface of the detergent granules than in the inner portion of thegranules, the tackiness of the granules can be suppressed.

As an example of methods of confirming the states of the above detergentgranules, there can be employed a method of utilizing both Fouriertransform infrared spectroscopy (FT-IR) and photoacoustic spectroscopy(PAS) in combination (simply abbreviated as “FT-IR/PAS”). As describedin “APPLIED SPECTROSCOPY,” Vol. 47, p. 1311–1316 (1993), in theFT-IR/PAS, spectra taken in the direction of from the surface to thedepths of the samples can be measured without changing the shapes of thesamples, so that it is possible to identify the distribution states ofthe substances in the direction of depth from the surface of thedetergent granules.

The concrete measurement method is as follows.

A cell is charged with samples to conduct FT-IR/PAS measurement, and themeasurement points taken at any depths up to about 20 μm from thesurface are analyzed. Concretely, in the phase modulation FT-IR/PASspectra at a constant phase modulation frequency, a magnitude spectrumat given phase angle is obtained by synchronously analyzing PAS spectralcomponents at a given phase angle and at an angle with a 90° phase shiftfrom the given phase angle. The FT-IR spectrum is measured, forinstance, by using an infrared spectrometer “FTS-60A/896” (manufacturedby Bio-Rad Laboratories), and the PAS cell includes an acoustic detector“Model 300” manufactured by MTEC Corporation. Scanning with aninterferometer is conducted by a step-scan method, and the modulationfrequency is set at 2.5 kHz. Peak intensities are detected from theobtained spectra for the sodium linear alkylbenzenesulfonate (LAS-Na)and sodium sulfate respectively at 1222 cm⁻¹ (SO₃ anti-symmetricstretching vibration) and 1149 cm⁻¹ (SO₄ stretching vibration).

A typical example of the above measurement is shown in FIG. 6. As isclear from in FIG. 6, in the case of the detergent granules obtainablein Example 11, it is found that the relative intensity of the peaksascribed to sodium sulfate, an inorganic salt (namely, the ratio betweenthe diffraction peak intensity of sodium sulfate and the diffractionpeak intensity of the LAS-Na) is high in the surface layer of thegranules when compared to the sodium sulfate which is present in theinner portion of the granules, i.e. the detergent granules haverelatively large contents of the inorganic salt present in the surfacelayer. By contrast, in the case of the detergent granules obtainable inComparative Example 11, the diffraction peak intensity ascribed to theinorganic salt shows substantially no changes from the inner portion ofthe granules to the surface layer of the granules, and when comparedwith Example 11, the diffraction peak intensity value is low andconstant. In addition, the tackiness of the granules (evaluated by thevalues of the fracture load) of each of the granules is 673 gf for thegranules of Example 11 in contrast to 1124 gf for the granules ofComparative Example 11, thereby showing that the detergent granules ofthe present invention are low-tackiness granules by forming an inorganicsalt on the surfaces of the granules by dry neutralization.

(2) Microporosity

The feature of the detergent granules of the present invention residesin having a large number of micropores in the granules in addition tohaving the low tackiness mentioned above. By having a larger number ofmicropores in the granules, it is considered that the liquid contentwhich can be retained in the micropores of the granules increases, sothat excess agglomeration of the granules owing to the bleeding out ofthe liquid starting materials during the production of granules can besuppressed. The microporous capacity in the granules can be measured,for instance, by known mercury pressure method (for example, a mercuryporosimeter “PORESIZER 9320,” manufactured by Shimadzu Corporation). Thedetergent granules of the present invention have a microporous capacitylarger than that of the detergent granules obtainable by conventionalmethod of dry neutralization.

In order to illustrate the effects of the size of the microporouscapacity, Example 18 and Comparative Example 16 may be compared as shownin FIG. 7.

FIG. 7 is a graph showing the relationship of the microporous diameterand the microporous capacity of the detergent compositions obtained inExample 18 and in Comparative Example 16. The microporous diameter ismeasured by a mercury porosimeter “PORESIZER 9320,” manufactured byShimadzu Corporation, and the microporous capacity is measured bymercury pressure method. The entire microporous capacity of thedetergent composition obtained in Example 18 is 0.402 mL/g, and theentire microporous surface areas of the detergent composition are 0.711m²/g. Also, the entire microporous capacity of the detergent compositionobtained in Comparative Example 16 is 0.327 mL/g, and the entiremicroporous surface areas of the detergent composition are 0.547 m²/g.

In Comparative Example 16, the molar ratio of the inorganic acid to theliquid acid precursor of a non-soap, anionic surfactant is 0.04, smallerthan the lower limit in the present invention. On the other hand, inExample 18, the detergent granules are produced by dry neutralizationunder the conditions that the molar ratio of the inorganic acid to theliquid acid precursor of a non-soap, anionic surfactant is 0.44. Whenthe entire microporous capacity and the microporous surface areas ofboth of the detergent granules are compared, all of the values arelarger in the detergent granules of Example 18 than those in thedetergent granules of Comparative Example 16. Also, the average particlesize of the detergent granules is 493 μm for Example 18 whereas theaverage particle size is 1313 μm for Comparative Example 16. From theseresults, it is considered that since the detergent granules of Example18 have larger entire microporous capacity and entire microporoussurface area than those of Comparative Example 16, the liquid contentwhich can be retained in the micropores in the granules increases, sothat excess agglomeration of the granules owing to the bleeding out ofthe liquid starting materials during the production of granules can besuppressed.

In the case where the detergent granules are designed or producedutilizing the above features of the detergent granules of the presentinvention, the following can be exemplified as preferred embodimentsaccording to its utility. Specifically,

-   (1) the detergent granules comprising a non-soap, anionic surfactant    and an inorganic salt undetectable by X-ray diffraction method,    wherein the amount of the non-soap, anionic surfactant is in an    amount of 28% by weight or more and less than 50% by weight, and a    molar ratio of [inorganic salt undetectable by X-ray diffraction    method]/[non-soap, anionic surfactant] is from 0.1 to 1.0; and-   (2) the detergent granules comprising a non-soap, anionic surfactant    and an inorganic salt undetectable by X-ray diffraction method,    wherein the amount of the non-soap, anionic surfactant in an amount    of 10% by weight or more and less than 28% by weight in the    detergent granules, and a molar ratio of [inorganic salt    undetectable by X-ray diffraction method]/[non-soap, anionic    surfactant] is from 0.3 to 1.0.    Detergent Granules of Embodiment (1)

In general, in the detergent granules containing large amounts of thenon-soap, anionic surfactant, it is difficult to produce the granuleshaving excellent free-flowability with small particle sizes. This isbecause the agglomeration of the granules is likely to take place owingto the tackiness inherently owned by the non-soap, anionic surfactant.Therefore, in the case, for instance, where the detergent granules areproduced by conventional method, the tackiness of the granules is likelyto give mal-effects during the production of the granules when thecontent of the non-soap, anionic surfactant is relatively large, forexample, when the content is 20% by weight or more in the granules, moreremarkably 28% by weight or more and less than 50% by weight,particularly remarkably 30% by weight or more and less than 50% byweight.

Therefore, it is preferred from the aspect of strongly exhibiting theeffects of suppressing their tackiness that the detergent granules ofthe present invention comprise a non-soap, anionic surfactant and aninorganic salt undetectable by X-ray diffraction method, wherein theamount of the non-soap, anionic surfactant is in an amount of 28% byweight or more and less than 50% by weight, and a molar ratio of[inorganic salt undetectable by X-ray diffraction method]/[non-soap,anionic surfactant] is from 0.1 to 1.0. Also, in the detergent granules,the molar ratio of [inorganic salt undetectable by X-ray diffractionmethod]/[non-soap, anionic surfactant] is more preferably from 0.1 to0.8, still more preferably from 0.15 to 0.65, particularly preferablyfrom 0.2 to 0.6, most preferably from 0.25 to 0.55.

Detergent Granules of Embodiment (2)

Also, when the microporous capacity of the granules is remarked, sincethe detergent granules of the present invention have a large microporouscapacity, the liquid components, such as nonionic surfactants, can beincluded in larger amounts in the micropores. From the above viewpoint,in a case where larger amounts of the liquid components, such asnonionic surfactants, are contained, there can be used as a preferredembodiment the detergent granules comprising a non-soap, anionicsurfactant and an inorganic salt undetectable by X-ray diffractionmethod, wherein the amount of the non-soap, anionic surfactant in anamount of 10% by weight or more and less than 28% by weight in thedetergent granules, and a molar ratio of [inorganic salt undetectable byX-ray diffraction method]/[non-soap, anionic surfactant] is from 0.3 to1.0. In the above detergent granules, it is more preferred that thenon-soap, anionic surfactant is contained in the detergent granules inan amount of 15% by weight or more and less than 28% by weight,particularly preferably from 15 to 26% by weight. From the viewpoint ofgiving high washing power, the amount of the non-soap, anionicsurfactant in the detergent granules is preferably 10% by weight ormore. From the viewpoint of suppressing the foaming of the detergentcomposition upon use, the amount is preferably less than 28% by weight.Also, the detergent granules in this embodiment have a molar ratio[inorganic salt undetectable by X-ray diffraction method]/[non-soap,anionic surfactant] of more preferably from 0.3 to 0.8, particularlypreferably 0.35 to 0.7.

The detergent granules of the present invention having the propertiesmentioned above may be used as such as a high-bulk density detergentcomposition, or the detergent granules may be used as one of componentsconstituting a detergent composition.

The amount of the liquid acid precursors of a non-soap, anionicsurfactants can be appropriately set depending upon the composition ofthe desired detergent composition. The amount of the liquid acidprecursors may be so added to include the anionic surfactants producedby the neutralization reaction in the final detergent compositionproduct in an amount of preferably from 5 to 50% by weight, morepreferably from 5 to 45% by weight, still more preferably from 10 to 40%by weight, particularly preferably from 20 to 40% by weight, withinwhich range the effects of the present invention can be remarkablyexhibited, which become particularly remarkable in the range where theamount of the anionic surfactant is large.

Also, it is more desired that the detergent granules of the presentinvention or the high-bulk density detergent composition comprising thedetergent granules obtainable by the method of the present inventionhave a bulk density of 500 g/L or more and that those detergent granuleshave the following properties.

Bulk density: Those having 650 to 950 g/L are preferred, those havingfrom 700 to 900 g/L are more preferred. In the present specification,the bulk density is a value evaluated by the method defined in JIS K3362;

Average particle size: As to the average particle size, from theviewpoint of solubility rate of the detergent granules, those having 850μm or less are preferred, those having from 300 to 800 μm are morepreferred. The proportion of the particles of 1400 μm or less, namelythe percentage of 1400 μm-pass particles, may vary in their suitableranges depending upon the concentration of the non-soap, anionicsurfactant in the resulting high-bulk density detergent composition. Forinstance, when the concentration of the non-soap, anionic surfactant isfrom 35 to 40% by weight, the percentage of 1400 μm-pass particles ispreferably 60% or more, more preferably 70% or more. When theconcentration of the non-soap, anionic surfactant is less than 35% byweight, the percentage of 1400 μm-pass particles is preferably 75% ormore, more preferably 80% or more. In the present specification, theaverage particle size of the detergent composition is obtained from theweight percentages depending on the sizes of the sieves after vibratinga standard sieve according to JIS K 8801 for five minutes, and thepercentage of 1400 μm-pass particles means the weight percentage of theproportion occupied by the particles of 1400 μm or less; and

-   -   Free-flowability: Evaluated in terms of flow time of preferably        8 seconds or less, more preferably 7 seconds or less. In the        present specification, the free-flowability of the detergent        composition is defined as a time period required for discharging        100 ml of powder from a hopper used in a measurement of bulk        density according to JIS K 3362.

The present invention will be explained in further detail by means ofthe following working examples and comparative examples, withoutintending to limit the scope of the present invention to these examples.

EXAMPLE 1

The detergent composition having the composition shown in Table 1 wasprepared in an amount of 35 kg for each unit using a high speed mixer“Lödige Mixer FKM-130D” (manufactured by Matsubo Co., Ltd.). This mixerwas equipped with agitator blades and a shearing device, the shearingdevice corresponding to a chopper for disintegration and dispersion.

Here, the following procedures were carried out.

Powder Blending

The solid ingredients consisting of 7.0 parts by weight of sodiumtripolyphosphate (STPP; average particle size: 11.2 μm), 12.61 parts byweight of sodium carbonate (“LIGHT ASH,” manufactured by Central GlassCo., Ltd.; average particle size: 56.1 μm), and 0.11 parts by weight ofa fluorescer were blended for one minute under the conditions of arotational speed of agitator blades of 130 rpm (peripheral speed: 3.4m/s) and a rotational speed of shearing device of 2850 rpm (peripheralspeed: 27 m/s) by the Lödige Mixer.

Addition of Reaction Initiating Agent

Water was added to the contents in the mixer in an amount of 0.20 partsby weight as a reaction initiating agent, and the blending was carriedout for one minute and thirty seconds under the same blending conditionsas above.

Neutralization

While the mixer was operated under the same conditions as above, 10.92parts by weight of a linear alkylbenzenesulfonic acid (LAS; molecularweight: 322) and 0.23 parts by weight of 98% sulfuric acid, which weremixed in advance, were added to the contents in the mixer in fourminutes. During the addition, the ingredients were cooled by allowingwater to flow through the mixer jacket at 25° C. At this stage, thetemperature rose to 75° C. at the highest. Incidentally, throughout thisstage, the reaction mixture remained in a granular form. Incidentally,the LAS mentioned above was obtained by SO₃ gas sulfonation method andcontained 0.16 parts by weight of sulfuric acid. In other words, theresulting mixture contained 0.05 mol of sulfuric acid per mol of theLAS. Also, the proportion of sulfuric acid to the LAS duringneutralization reaction was such that the reaction mixture contained0.12 mol of sulfuric acid per mol of the LAS. The amount of sodiumcarbonate was about six times the amount required for neutralizing theLAS and sulfuric acid.

After the addition of the LAS, the mixer was continuously operated underthe same conditions for one minute to complete the neutralizationreaction and the granulation process.

Addition of Liquid Ingredients and Surface Modification

At a point where the neutralization reaction and the granulation processwere completed, an aqueous solution of a 40% by weight acrylicacid-maleic acid copolymer was added to the mixer with an effectiveamount of the copolymer being 0.18 parts by weight, while the mixer wasoperated under the same conditions as above, and the ingredients weremixed for one minute and thirty seconds. Thereafter, the resultingmixture was subjected to a surface modification treatment by adding 4.20parts by weight of zeolite having an average particle size of 4 μm tothe mixer as a surface modifier, and operating the mixer for additionaltwo minutes. Incidentally, the zeolite contained 0.84 parts by weight ofa crystal water.

The resulting granules of the detergent composition had percentage ofparticles with 1400 μm-pass: 75.3%; average particle size: 633 μm; bulkdensity: 760 g/L; free-flowability: 6.2 seconds; and hue: 92.4.Accordingly, the granules showed excellent properties.

After-Blending

Using a rotary mixer, 0.18 parts by weight of enzyme granules and thedetergent composition obtained above were blended, and thereafter 0.07parts by weight of perfume were sprayed, to give a final powdery productof the high-bulk density detergent composition.

EXAMPLE 2

Similar composition and procedures to those in Example 1 were employedexcept for respectively changing the amounts of LIGHT ASH and sulfuricacid to 12.45 parts by weight and 0.57 parts by weight, to give adetergent composition. The fracture load of the granules obtained afterthe neutralization and granulation step was 742 gf, and the averageparticle size of the granules was 632 μm.

The resulting granules of the detergent composition, prior to theafter-blending step, had percentage of particles with 1400 μm-pass:82.6%; average particle size: 517 μm; bulk density: 730 g/L;free-flowability: 6.3 seconds; and hue: 91.4. Accordingly, the granulesshowed excellent properties.

Incidentally, the proportion of sulfuric acid to the LAS duringneutralization reaction was such that the reaction mixture contained0.23 mol of sulfuric acid per mol of the LAS. The amount of sodiumcarbonate was about five times the amount required for neutralizing theLAS and sulfuric acid.

EXAMPLE 3

Similar composition and procedures to those in Example 1 were employedexcept for respectively changing the amounts of LIGHT ASH and sulfuricacid to 12.33 parts by weight and 0.82 parts by weight, to give adetergent composition.

The resulting granules of the detergent composition, prior to theafter-blending step, had percentage of particles with 1400 μm-pass:83.8%; average particle size: 496 μm; bulk density: 717 g/L;free-flowability: 6.2 seconds; and hue: 91.5. Accordingly, the granulesshowed excellent properties.

Incidentally, the proportion of sulfuric acid to the LAS duringneutralization reaction was such that the reaction mixture contained 0.3mol of sulfuric acid per mol of the LAS. The amount of sodium carbonatewas about four times the amount required for neutralizing the LAS andsulfuric acid.

EXAMPLE 4

Similar composition and procedures to those in Example 1 were employedexcept for respectively changing the amounts of LIGHT ASH, the LAS, andsulfuric acid to 11.11 parts by weight, 12.29 parts by weight, and 0.80parts by weight, to give a detergent composition. Incidentally, the LASmentioned above contained 0.18 parts by weight of sulfuric acid.

The resulting granules of the detergent composition, prior to theafter-blending step, had percentage of particles with 1400 μm-pass:70.0%; average particle size: 703 μm; bulk density: 694 g/L;free-flowability: 6.5 seconds; and hue: 91.0. Accordingly, the granulesshowed excellent properties.

Incidentally, the proportion of sulfuric acid to the LAS duringneutralization reaction was such that the reaction mixture contained0.27 mol of sulfuric acid per mol of the LAS. The amount of sodiumcarbonate was about four times the amount required for neutralizing theLAS and sulfuric acid.

EXAMPLE 5

The detergent composition having the composition shown in Table 1 wasprepared in an amount of 35 kg for each unit using a high speed mixer“Lödige Mixer FKM-130D” (manufactured by Matsubo Co., Ltd.). This mixerwas equipped with agitator blades and a shearing device, the shearingdevice corresponding to a chopper for disintegration and dispersion.

Here, the following procedures were carried out.

Powder Blending

The solid ingredients consisting of 20.06 parts by weight of sodiumcarbonate (“LIGHT ASH,” manufactured by Central Glass Co., Ltd.; averageparticle size: 56.1 μm) were blended for one minute under the conditionsof a rotational speed of agitator blades of 130 rpm and a rotationalspeed of shearing device of 2850 rpm by the Lödige Mixer.

Addition of Reaction Initiating Agent

Water was added to the contents in the mixer in an amount of 0.25 partsby weight as a reaction initiating agent, and the blending was carriedout for one minute and thirty seconds under the same blending conditionsas above.

Neutralization

While the mixer was operated under the same conditions as above, 10.92parts by weight of a linear alkylbenzenesulfonic acid (LAS) and 0.82parts by weight of 98% sulfuric acid, which were mixed in advance, wereadded to the contents in the mixer in four minutes. During the addition,the ingredients were cooled by allowing water to flow through the mixerjacket at 25° C. At this stage, the temperature rose to 81° C. at thehighest. Incidentally, throughout this stage, the reaction mixtureremained in a granular form. Incidentally, the LAS mentioned abovecontained 0.16 parts by weight of sulfuric acid. Also, the proportion ofsulfuric acid to the LAS during neutralization reaction was such thatthe reaction mixture contained 0.3 mol of sulfuric acid per mol of theLAS. The amount of sodium carbonate was about seven times the amountrequired for neutralizing the LAS and sulfuric acid.

After the addition of the LAS, the mixer was continuously operated underthe same conditions for one minute to complete the neutralizationreaction and the granulation process.

The resulting granules of the detergent composition had percentage ofparticles with 1400 μm-pass: 81.0%; average particle size: 604 μm; bulkdensity: 707 g/L; free-flowability: 6.5 seconds; and hue: 91.1.Accordingly, the granules showed excellent properties.

EXAMPLE 6

Similar composition and procedures to those in Example 3 were employedexcept for not containing sodium tripolyphosphate at all and makingzeolite as a main builder component, to give a detergent composition.

The resulting granules of the detergent composition, prior to theafter-blending step, had percentage of particles with 1400 μm-pass:83.9%; average particle size: 536 μm; bulk density: 737 g/L;free-flowability: 6.3 seconds; and hue: 90.2. Accordingly, the granulesshowed excellent properties.

EXAMPLE 7

Similar composition and procedures to those in Example 3 were employedexcept for using sodium tripolyphosphate having an average particle sizeof 58.4 μm, to give a detergent composition.

The resulting granules of the detergent composition, prior to theafter-blending step, had percentage of particles with 1400 μm-pass:82.3%; average particle size: 532 μm; bulk density: 760 g/L;free-flowability: 6.3 seconds; and hue: 90.8. Accordingly, the granulesshowed excellent properties.

COMPARATIVE EXAMPLE 1

The detergent composition having the composition shown in Table 2 wasprepared in an amount of 35 kg for each unit using a high speed mixer“Lödige Mixer FKM-130D” (manufactured by Matsubo Co., Ltd.). This mixerwas equipped with agitator blades and a shearing device, the shearingdevice corresponding to a chopper for disintegration and dispersion.

Here, the following procedures were carried out.

Powder Blendinq

The solid ingredients consisting of 7.0 parts by weight of sodiumtripolyphosphate (STPP; average particle size: 11.2 μm), 12.69 parts byweight of sodium carbonate (“LIGHT ASH,” manufactured by Central GlassCo., Ltd.; average particle size: 56.1 μm), and 0.11 parts by weight ofa fluorescer were blended for one minute under the conditions of arotational speed of agitator blades of 130 rpm and a rotational speed ofshearing device of 2850 rpm by the Lödige Mixer.

Addition of Reaction Initiating Agent

Water was added to the contents in the mixer in an amount of 0.20 partsby weight as a reaction initiating agent, and the blending was carriedout for one minute and thirty seconds under the same blending conditionsas above.

Neutralization

While the mixer was operated under the same conditions as above, 10.92parts by weight of a linear alkylbenzenesulfonic acid (LAS) were addedto the contents in the mixer in four minutes. During the addition, theingredients were cooled by allowing water to flow through the mixerjacket at 25° C. At this stage, the temperature rose to 73° C. at thehighest. Incidentally, throughout this stage, the reaction mixtureremained in a granular form. Incidentally, the LAS mentioned abovecontained 0.16 parts by weight of sulfuric acid. Also, the proportion ofsulfuric acid to the LAS during neutralization reaction was such thatthe reaction mixture contained 0.05 mol of sulfuric acid per mol of theLAS.

After the addition of the LAS, the mixer was continuously operated underthe same conditions for one minute to complete the neutralizationreaction and the granulation process. The fracture load of the granulesobtained in this Example was 1215 gf, and the average particle size ofthe granules was 1114 μm.

Addition of Liquid Ingredients and Surface Modification

At a point where the neutralization reaction and the granulation processwere completed, an aqueous solution of a 40% by weight acrylicacid-maleic acid copolymer was added to the mixer with an effectiveamount of the copolymer being 0.18 parts by weight, while the mixer wasoperated under the same conditions as above, and the ingredients weremixed for one minute and thirty seconds. Thereafter, the resultingmixture was subjected to a surface modification treatment by adding 4.20parts by weight of zeolite having an average particle size of 4 μm tothe mixer as a surface modifier, and operating the mixer for additionaltwo minutes. Incidentally, the zeolite contained 0.84 parts by weight ofa crystal water.

The resulting granules of the detergent composition had percentage ofparticles with 1400 μm-pass: 67.4%; average particle size: 739 μm; bulkdensity: 830 g/L; free-flowability: 6.1 seconds; and hue: 91.6.Accordingly, the granules gave poorer results in the percentage ofparticles and in the average particle size than the granules ofExamples.

After-Blending

Using a rotary mixer, 0.18 parts by weight of enzyme granules and thedetergent composition obtained above were blended, and thereafter 0.07parts by weight of perfume were sprayed, to give a final powdery productof the high-bulk density detergent composition.

Incidentally, the amount of sodium carbonate was about seven times theamount required for neutralizing the LAS and sulfuric acid.

COMPARATIVE EXAMPLE 2

The detergent composition having the composition shown in Table 2 wasprepared in an amount of 35 kg for each unit using a high speed mixer“Lödige Mixer FKM-130D” (manufactured by Matsubo Co., Ltd.). This mixerwas equipped with agitator blades and a shearing device, the shearingdevice corresponding to a chopper for disintegration and dispersion.

Here, the following procedures were carried out.

Powder Blending

The solid ingredients consisting of 7.0 parts by weight of sodiumtripolyphosphate (STPP; average particle size: 11.2 μm), 11.53 parts byweight of sodium carbonate (“LIGHT ASH,” manufactured by Central GlassCo., Ltd.; average particle size: 56.1 μm), 0.11 parts by weight of afluorescer, and 1.16 parts by weight of sodium sulfate (prepared bypulverizing to an average particle size of 8.22 μm by a hammer mill)were blended for one minute under the conditions of a rotational speedof agitator blades of 130 rpm and a rotational speed of shearing deviceof 2850 rpm by the Lödige Mixer.

Addition of Reaction Initiating Agent

Water was added to the contents in the mixer in an amount of 0.20 partsby weight as a reaction initiating agent, and the blending was carriedout for one minute and thirty seconds under the same blending conditionsas above.

Neutralization

While the mixer was operated under the same conditions as above, 10.92parts by weight of a linear alkylbenzenesulfonic acid (LAS) were addedto the contents in the mixer in four minutes. During the addition, theingredients were cooled by allowing water to flow through the mixerjacket at 25° C. At this stage, the temperature rose to 72° C. at thehighest. Incidentally, throughout this stage, the reaction mixtureremained in a granular form. Incidentally, the LAS mentioned abovecontained 0.16 parts by weight of sulfuric acid. Also, the proportion ofsulfuric acid to the LAS during neutralization reaction was such thatthe reaction mixture contained 0.05 mol of sulfuric acid per mol of theLAS.

After the addition of the LAS, the mixer was continuously operated underthe same conditions for one minute to complete the neutralizationreaction and the granulation process.

Addition of Liquid Ingredients and Surface Modification

At a point where the neutralization reaction and the granulation processwere completed, an aqueous solution of a 40% by weight acrylicacid-maleic acid copolymer was added to the mixer with an effectiveamount of the copolymer being 0.18 parts by weight, while the mixer wasoperated under the same conditions as above, and the ingredients weremixed for one minute and thirty seconds. Thereafter, the resultingmixture was subjected to a surface modification treatment by adding 4.20parts by weight of zeolite having an average particle size of 4 μm tothe mixer as a surface modifier, and operating the mixer for additionaltwo minutes. Incidentally, the zeolite contained 0.84 parts by weight ofa crystal water.

The resulting granules of the detergent composition had percentage ofparticles with 1400 μm-pass: 68.0%; average particle size: 720 μm; bulkdensity: 786 g/L; free-flowability: 6.3 seconds; and hue: 90.8.Accordingly, the granules gave poorer results in the percentage ofparticles and in the average particle size than the granules ofExamples.

After-Blending

Using a rotary mixer, 0.18 parts by weight of enzyme granules and thedetergent composition obtained above were blended, and thereafter 0.07parts by weight of perfume were sprayed, to give a final powdery productof the high-bulk density detergent composition.

Incidentally, the amount of sodium carbonate was about seven times theamount required for neutralizing the LAS and sulfuric acid.

COMPARATIVE EXAMPLE 3

The detergent composition having the composition shown in Table 2 wasprepared in an amount of 35 kg for each unit using a high speed mixer“Lödige Mixer FKM-130D” (manufactured by Matsubo Co., Ltd.). This mixerwas equipped with agitator blades and a shearing device, the shearingdevice corresponding to a chopper for disintegration and dispersion.

Here, the following procedures were carried out.

Powder Blending

The solid ingredients consisting of 7.0 parts by weight of sodiumtripolyphosphate (STPP; average particle size: 11.2 μm), 11.43 parts byweight of sodium carbonate (“LIGHT ASH,” manufactured by Central GlassCo., Ltd.; average particle size: 56.1 μm), and 0.11 parts by weight ofa fluorescer were blended for one minute under the conditions of arotational speed of agitator blades of 130 rpm and a rotational speed ofshearing device of 2850 rpm by the Lödige Mixer.

Addition of Reaction Initiating Agent

Water was added to the contents in the mixer in an amount of 0.20 partsby weight as a reaction initiating agent, and the blending was carriedout for one minute and thirty seconds under the same blending conditionsas above.

Neutralization

While the mixer was operated under the same conditions as above, 12.29parts by weight of a linear alkylbenzenesulfonic acid (LAS) were addedto the contents in the mixer in four minutes. During the addition, theingredients were cooled by allowing water to flow through the mixerjacket at 25° C. At this stage, the temperature rose to 73° C. at thehighest. Incidentally, throughout this stage, the reaction mixtureremained in a granular form. Incidentally, the LAS mentioned abovecontained 0.18 parts by weight of sulfuric acid. Also, the proportion ofsulfuric acid to the LAS during neutralization reaction was such thatthe reaction mixture contained 0.05 mol of sulfuric acid per mol of theLAS.

After the addition of the LAS, the mixer was continuously operated underthe same conditions for one minute to complete the neutralizationreaction and the granulation process.

Addition of Liquid Ingredients and Surface Modification

At a point where the neutralization reaction and the granulation processwere completed, an aqueous solution of a 40% by weight acrylicacid-maleic acid copolymer was added to the mixer with an effectiveamount of the copolymer being 0.18 parts by weight, while the mixer wasoperated under the same conditions as above, and the ingredients weremixed for one minute and thirty seconds. Thereafter, the resultingmixture was subjected to a surface modification treatment by adding 4.20parts by weight of zeolite having an average particle size of 4 μm tothe mixer as a surface modifier, and operating the mixer for additionaltwo minutes. Incidentally, the zeolite contained 0.84 parts by weight ofa crystal water.

The resulting granules of the detergent composition had percentage ofparticles with 1400 μm-pass: 32.5%; average particle size: 1469 μm; bulkdensity: 736 g/L; free-flowability: 6.4 seconds; and hue: 91.4.Accordingly, the granules gave poorer results in the percentage ofparticles with a large proportion of coarse particles.

After-Blending

Using a rotary mixer, 0.18 parts by weight of enzyme granules and thedetergent composition obtained above were blended, and thereafter 0.07parts by weight of perfume were sprayed, to give a final powdery productof the high-bulk density detergent composition.

In this Comparative Example, the amount of sodium carbonate was aboutfive times the amount required for neutralizing the LAS and sulfuricacid.

COMPARATIVE EXAMPLE 4

The detergent composition having the composition shown in Table 2 wasprepared in an amount of 35 kg for each unit using a high speed mixer“Lödige Mixer FKM-130D” (manufactured by Matsubo Co., Ltd.). This mixerwas equipped with agitator blades and a shearing device, the shearingdevice corresponding to a chopper for disintegration and dispersion.

Here, the following procedures were carried out.

Powder Blending

The solid ingredients consisting of 7.0 parts by weight of sodiumtripolyphosphate (STPP; average particle size: 58.4 μm), 12.69 parts byweight of sodium carbonate (“LIGHT ASH,” manufactured by Central GlassCo., Ltd.; average particle size: 56.1 μm), and 0.11 parts by weight ofa fluorescer were blended for one minute under the conditions of arotational speed of agitator blades of 130 rpm and a rotational speed ofshearing device of 2850 rpm by the Lödige Mixer.

Addition of Reaction Initiating Agent

Water was added to the contents in the mixer in an amount of 0.20 partsby weight as a reaction initiating agent, and the blending was carriedout for one minute and thirty seconds under the same blending conditionsas above.

Neutralization

While the mixer was operated under the same conditions as above, 10.92parts by weight of a linear alkylbenzenesulfonic acid (LAS) were addedto the contents in the mixer in four minutes. During the addition, theingredients were cooled by allowing water to flow through the mixerjacket at 25° C. At this stage, the temperature rose to 71° C. at thehighest. Incidentally, throughout this stage, the reaction mixtureremained in a granular form. Incidentally, the LAS mentioned abovecontained 0.16 parts by weight of sulfuric acid.

After the addition of the LAS, the mixer was continuously operated underthe same conditions for one minute to complete the neutralizationreaction and the granulation process.

Addition of Liquid Ingredients and Surface Modification

At a point where the neutralization reaction and the granulation processwere completed, an aqueous solution of a 40% by weight acrylicacid-maleic acid copolymer was added to the mixer with an effectiveamount of the copolymer being 0.18 parts by weight, while the mixer wasoperated under the same conditions as above, and the ingredients weremixed for one minute and thirty seconds. Thereafter, the resultingmixture was subjected to a surface modification treatment by adding 4.20parts by weight of zeolite having an average particle size of 4 μm tothe mixer as a surface modifier, and operating the mixer for additionaltwo minutes. Incidentally, the zeolite contained 0.84 parts by weight ofa crystal water.

The resulting granules of the detergent composition had percentage ofparticles with 1400 μm-pass: 34.2%; average particle size: 1013 μm; bulkdensity: 712 g/L; and free-flowability: 7.8 seconds. Accordingly, thegranules gave low bulk density and poor results in the percentage ofparticles with a large proportion in coarse particles.

After-Blending

Using a rotary mixer, 0.18 parts by weight of enzyme granules and thedetergent composition obtained above were blended, and thereafter 0.07parts by weight of perfume were sprayed, to give a final powdery productof the high-bulk density detergent composition.

Incidentally, the amount of sodium carbonate was about seven times theamount required for neutralizing the LAS and sulfuric acid.

Incidentally, Tables 1 and 2 show the compositions of the final powderyproduct of each of the detergent compositions in Examples andComparative Examples. Also, Tables 3 and 4 show the properties of thedetergent compositions after granulation.

TABLE 1 Composition of Final Powdery Product of Detergent CompositionExamples (% by weight) 1 2 3 4 5 6 7 LAS-Na 32.00 32.00 32.00 36.0032.00 32.00 32.00 STPP 20.00 20.00 20.00 20.00 0.00 0.00 20.00 Zeolite12.00 12.00 12.00 12.00 12.00 32.00 12.00 Sodium Carbonate 29.90 28.4027.30 23.20 49.40 27.80 27.30 Sodium Sulfate 1.60 3.00 4.00 4.00 4.004.00 4.00 Acrylic Acid-Maleic 0.50 0.50 0.50 0.50 0.00 0.50 0.50 AcidCopolymer Fluorescent 0.30 0.30 0.30 0.30 0.00 0.30 0.30 Enzymes 0.500.50 0.50 0.50 0.00 0.50 0.50 Perfume 0.20 0.20 0.20 0.20 0.00 0.20 0.20Water 3.00 3.10 3.20 3.30 2.60 2.70 3.20

TABLE 2 Composition of Final Powdery Product of Detergent CompositionComparative Examples (% by weight) 1 2 3 4 LAS-Na 32.00 32.00 36.0032.00 STPP 20.00 20.00 20.00 20.00 Zeolite 12.00 12.00 12.00 12.00Sodium Carbonate 30.82 27.50 26.54 30.82 Sodium Sulfate 0.68 4.00 0.760.68 Acrylic Acid-Maleic Acid 0.50 0.50 0.50 0.50 Copolymer Fluorescent0.30 0.30 0.30 0.30 Enzymes 0.50 0.50 0.50 0.50 Perfume 0.20 0.20 0.200.20 Water 3.00 3.00 3.20 3.00

TABLE 3 Examples 1 2 3 4 5 6 7 Average Particle 11.2 11.2 11.2 11.2 — —58.4 Size (μm) of STPP Average Particle 56.1 56.1 56.1 56.1 56.1 56.156.1 Size (μm) of LIGHT ASH Highest Powder 75 77 80 83 81 81 79 Temp. (°C.) Average Particle 633 517 496 703 604 536 532 Size (μm) Yield(Percentage of 75.3 82.6 83.8 70.0 81.0 83.9 82.3 1140 μm-passParticles) (%) Bulk Density (g/L) 760 730 717 694 707 737 760 FreeFlowability (sec) 6.2 6.3 6.2 6.5 6.5 6.3 6.3 Hue (L value) 92.44 91.491.5 91.0 91.1 90.2 90.8

TABLE 4 Comparative Examples 1 2 3 4 Average Particle 11.2 11.2 11.258.4 Size (μm) of STPP Average Particle 56.1 56.1 56.1 56.1 Size (μm) ofLIGHT ASH Highest Powder 73 72 73 71 Temp. (° C.) Average Particle 739720 1469 1013 Size (μm) Yield (Percentage of 67.4 68.0 32.5 34.2 1400μm-pass Particles) (%) Bulk Density (g/L) 830 786 736 712 FreeFlowability (sec) 6.1 6.3 6.4 7.8 Hue (L value) 91.6 90.8 91.4 91.8

As is clearly illustrated by the above results, by dry-neutralizing thecomponents in the presence of a given amount of sulfuric acid, thehigh-bulk density detergent compositions having small particle sizes canbe obtained at high yields (Examples 1 to 7). Also, as illustrated byExample 5 and Example 6, the method of the present invention can besuitably utilized to give desired effects without being limitative inthe detergent compositions. Also, the method is particularly applicablefor production of phosphorus-free detergents.

On the other hand, in the case of Comparative Example 1 where a smalleramount of sulfuric acid is used during neutralization, the granules arelarge, showing poorer results in the percentage of particles with 1400μm-pass and in the average particle size as compared to Examples. Also,in the case of Comparative Example 2 where pulverized sodium sulfate isadded, the resulting detergent granules have large particle size. Bycomparing Example 4 with Comparative Example 3, remarkable differencesin the percentage of particles with 1400 μm-pass and in the averageparticle size can be noted when the concentration of the anionicsurfactant (LAS-Na) in the resulting detergent composition is as high as36.00% by weight. Therefore, the method of the present invention can besuitably applied in cases where the anionic surfactant is contained at ahigh concentration in the detergent composition. By comparing Example 7and Comparative Example 4, even when the particle size of thetripolyphosphate is relatively large (58.4 μm), the effects of themethod of the present invention can be clearly observed. Incidentally,in Example 1, Example 2, and Example 3, a decrease in the bulk densitiescan be observed by an increase in the amount of sulfuric acid, therebysuggesting that the bulk densities of the resulting detergentcompositions can be controlled to desired values by the amount ofsulfuric acid added. Incidentally, the detergent compositions obtainedin each of Examples were subjected to X-ray diffraction analysis, but nodiffraction peaks ascribed to sodium sulfate were detectable.

EXAMPLE 11

The detergent composition having the composition shown in Table 5 wasprepared in an amount of 35 kg for each unit using a high speed mixer“Lödige Mixer FKM-130D” (manufactured by Matsubo Co., Ltd.). This mixerwas equipped with agitator blades and a shearing device, the shearingdevice corresponding to a chopper for disintegration and dispersion.

Here, the following procedures were carried out.

Powder Blending

The solid ingredients consisting of 7.0 parts by weight of sodiumtripolyphosphate (STPP; average particle size: 11.2 μm), 12.72 parts byweight of sodium carbonate (“LIGHT ASH,” manufactured by Central GlassCo., Ltd.; average particle size: 56.1 μm), and 0.11 parts by weight ofa fluorescer were blended for one minute under the conditions of arotational speed of agitator blades of 130 rpm (peripheral speed: 3.4m/s) and a rotational speed of shearing device of 2850 rpm (peripheralspeed: 27 m/s) by the Lödige Mixer.

Addition of Reaction Initiating Agent

A 48% by weight aqueous NaOH solution was added to the contents in themixer in an amount of 0.51 parts by weight as a reaction initiatingagent, and the blending was carried out for one minute and thirtyseconds under the same blending conditions as above.

Neutralization

While the mixer was operated under the same conditions as above, 10.19parts by weight of a linear alkylbenzenesulfonic acid (LAS; molecularweight: 322) and 0.58 parts by weight of 98% sulfuric acid, which weremixed in advance, were added to the contents in the mixer in fourminutes. During the addition, the ingredients were cooled by allowingwater to flow through the mixer jacket at 25° C. Incidentally,throughout this stage, the reaction mixture remained in a granular form.Incidentally, the LAS mentioned above was prepared by SO₃ gassulfonation method and contained 0.16 parts by weight of sulfuric acid.In other words, the resulting mixture contained 0.05 mol of sulfuricacid per mol of the LAS. Also, the proportion of sulfuric acid to theLAS during neutralization reaction was such that the reaction mixturecontained 0.24 mol of sulfuric acid per mol of the LAS. The amount ofsodium carbonate was about five times the amount required forneutralizing the LAS and sulfuric acid.

After the addition of the LAS, the mixer was continuously operated underthe same conditions for three minutes to complete the neutralizationreaction and the granulation process. Also, air was blown at a rate of300 L/min immediately after the addition of the mixed acid.

Addition of Liquid Ingredients and Surface Modification

At a point where the neutralization reaction and the granulation processwere completed, an aqueous solution of a 40% by weight acrylicacid-maleic acid copolymer was added to the mixer with an effectiveamount of the copolymer being 0.44 parts by weight, while the mixer wasoperated under the same conditions as above, and the ingredients weremixed for one minute and thirty seconds. Thereafter, the resultingmixture was subjected to a surface modification treatment by adding 4.20parts by weight of zeolite having an average particle size of 4 μm tothe mixer as a surface modifier, and operating the mixer for additionaltwo minutes. Incidentally, the zeolite contained 0.84 parts by weight ofa crystal water.

The resulting granules of the detergent composition had percentage ofparticles with 1400 μm-pass: 83.8%; average particle size: 469 μm; bulkdensity: 753 g/L; free-flowability: 6.3 seconds. Accordingly, thegranules showed excellent properties.

After-Blending

Using a rotary mixer, 0.18 parts by weight of enzyme granules and thedetergent composition obtained above were blended, and thereafter 0.07parts by weight of perfume were sprayed, to give a final powdery productof the high-bulk density detergent composition.

EXAMPLES 12–22 AND COMPARATIVE EXAMPLES 11–19

Similar composition and procedures to those in Example 11 were employedexcept for using the starting materials listed in Tables 5 and 6 inamounts shown in the tables, to give each of the final powdery productsof the high-bulk density detergent compositions. Here, in Examples 18 to20, after completing given procedures for the neutralization process,additional components of fatty acid (having 14 to 18 carbon atoms) and anonionic surfactant (having ethylene oxide moiety with 6 addition molarnumber) were added to the ingredients in the mixture in given amountsshown in Table 5, and the ingredients were blended for one minute. Thecomposition and the properties of each of the resulting high-bulkdensity detergent compositions are listed in Tables 7 through 10.

Incidentally, the fracture load was measured by using a rheometer“NRA-3002D” (manufactured by Fudohkogyo K.K.).

TABLE 5 Composition Examples (parts by weight) 11 12 13 14 15 16 17 1819 20 21 22 Powder Blending STPP 7.00 7.00 7.00 7.00 5.95 7.00 7.00 7.707.70 — — 7.00 Sodium Carbonate 12.72 12.06 11.78 13.36 14.11 10.40 9.3712.95 13.99 13.99 12.65 10.97 Zeolite — — — — — — — — — 7.70 7.00 —Powdery Sodium Sulfate — — — — — — — — — — — 1.75 Fluorescer 0.11 0.110.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 Addition of ReactionInitiating Agent 48 wt %-Aqueous 0.51 0.51 0.51 — — 0.61 0.66 0.37 0.27— — 0.51 NaOH Solution Neutralization LAS 10.19 10.19 10.19 10.19 10.1912.22 13.24 7.47 5.43 5.43 10.19 10.19 98 wt % Sulfuric Acid 0.58 1.822.31 0.58 — 1.29 1.40 0.87 0.90 0.90 1.08 0.58 85 wt % Phosphoric Acid —— — — 0.74 — — — — — — — (Amount of Gas Blown) 300 300 300 300 300 300300 300 300 300 300 300 [L/min] Fatty Acid — — — — — — — 0.49 0.49 0.49— — Nonionic Surfactant — — — — — — — 1.40 2.45 2.45 — — Addition ofLiquid Ingredients and Surface Modification Acrylic Acid-Maleic 0.440.44 0.44 0.44 0.44 0.44 0.44 — — — 0.44 0.44 Acid Copolymer Zeolite4.20 4.20 4.20 4.20 4.20 4.20 4.20 4.20 4.20 4.20 4.20 4.20After-Blending Enzyme 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.180.18 0.18 Perfume 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.070.07 Molar Ratio of Inorganic 0.24 0.65 0.81 0.24 0.28 0.40 0.40 0.440.65 0.65 0.40 0.24 Acid/Liquid Acid Precursor [mol/mol]

TABLE 6 Composition Comparative Examples (parts by weight) 11 12 13 1415 16 17 18 19 Powder Blending STPP 7.00 7.00 7.00 7.00 7.00 7.70 7.70 —— Sodium Carbonate 13.05 13.68 12.20 11.06 10.10 13.26 14.34 14.34 13.22Zeolite — — — — — — — 7.70 7.70 Powdery Sodium Sulfate — — 0.90 — — — —— — Fluorescer 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.11 Addition ofReaction Initiating Agent 48 wt %-Aqueous 0.51 — 0.51 0.61 0.66 0.370.27 0.27 — NaOH Solution Neutralization LAS 10.19 10.19 10.19 12.2213.24 7.47 5.43 5.43 10.19 98 wt % Sulfuric Acid — — — — — — — — — 85 wt% Phosphoric Acid — — — — — — — — — (Amount of Gas Blown) 300 300 300300 300 300 300 300 300 [L/min] Fatty Acid — — — — — 0.49 0.49 0.49 —Nonionic Surfactant — — — — — 1.40 2.45 2.45 — Addition of LiquidIngredients and Surface Modification Acrylic Acid-Maleic 0.44 0.44 0.440.44 0.44 — — — 0.44 Acid Copolymer Zeolite 4.20 4.20 4.20 4.20 4.204.20 4.20 4.20 4.20 After-Blending Enzyme 0.18 0.18 0.18 0.18 0.18 0.180.18 0.18 0.18 Perfume 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07Molar Ratio of Inorganic 0.04 0.04 0.04 0.04 0.04 0.04 0.03 0.03 0.04Acid/Liquid Acid Precursor [mol/mol]

TABLE 7 Examples Properties 11 12 13 14 15 16 17 18 19 20 21 22 AfterNeutralization and Granulation Process Powder Temp. [° C.] 80.1 87.392.3 79.2 73.7 84.3 90.0 79.4 72.0 68.8 80.8 79.5 Fracture Load [gf] 673520 470 690 930 850 950 226 57 51 502 659 Average Particle 560 488 450583 570 850 1785 290 241 339 580 545 Size [μm] After SurfaceModification Process Powder Temp. [° C.] 69.5 71.1 74.5 68.1 64.2 70.975.4 66.5 63.2 58.5 61.0 68.2 Average Particle 469 400 380 490 470 6701567 493 445 494 450 458 Size [μm] Yield [%] 83.8 86.0 87.0 83.1 79.273.0 30.0 87.9 78.9 78.8 79.1 84.0 Bulk Density [g/L] 753 723 724 731816 725 719 791 831 818 747 748 Free Flowability [sec] 6.3 6.6 6.8 6.46.1 6.4 6.8 6.0 6.1 6.6 6.8 6.5

TABLE 8 Comparative Examples Properties 11 12 13 14 15 16 17 18 19 AfterNeutralization and Granulation Process Powder Temp. [° C.] 73.0 68.973.1 76.8 ※ 68.1 60.1 56.7 67.8 Fracture Load [gf] 1124 1163 1100 1606 ※723 130 147 948 Average Particle 879 970 940 3055 ※ 390 299 463 750 Size[μm] After Surface Modification Process Powder Temp. [° C.] 64.5 62.662.1 63.5 ※ 58.5 55.1 54.3 55.4 Average Particle 670 710 720 2033 ※ 13131173 964 590 Size [μm] Yield [%] 69.8 63.7 65.0 12.0 ※ 53.2 32.9 57.476.3 Bulk Density [g/L] 841 788 831 692 ※ 847 864 848 769 FreeFlowability [sec] 6.2 6.4 6.3 8.7 ※ 6.1 6.6 6.9 6.9 Remarks ※: Theneutralized product became highly sticky, and thus no measurements couldbe taken. @

TABLE 9 Examples (parts by weight) 11 12 13 14 15 16 17 18 19 20 21 22Las-Na 30.00 30.00 30.00 30.00 30.00 36.00 39.00 22.00 16.00 16.00 30.0030.00 Soap 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.50 1.50 1.50 0.00 0.00STPP 20.00 20.00 20.00 20.00 17.00 20.00 20.00 22.00 22.00 0.00 0.0020.00 Zeolite 12.00 12.00 12.00 12.00 12.00 12.00 12.00 12.00 12.0034.00 32.00 12.00 Sodium Carbonate 30.40 24.80 22.50 31.30 32.30 20.8017.10 31.30 35.00 35.00 28.70 25.40 Sodium Sulfate* 3.00 8.00 10.00 3.000.50 6.00 6.50 4.00 4.00 4.00 5.00 8.00 Sodium Phosphate 0.00 0.00 0.000.00 3.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Acrylic Acid-Maleic 0.500.50 0.50 0.50 0.50 0.50 0.50 0.00 0.00 0.00 0.50 0.50 Acid CopolymerNonionic Surfactant 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.00 7.00 7.000.00 0.00 Fluorescer 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.300.30 0.30 Enzyme 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.500.50 Perfume 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20Water 3.10 3.70 4.00 2.20 3.70 3.70 3.90 2.20 1.50 1.50 2.80 3.10 SodiumSulfate** 3.14 8.43 11.14 n.t. n.t. 6.14 6.57 4.55 n.t. n.t. 5.43 n.t.Remarks *: Amount calculated from starting material composition. **:Amount chemically determined by ion chromatography. n.t.: Not tested.

TABLE 10 Comparative Examples (parts by weight) 11 12 13 14 15 16 17 1819 Las-Na 30.00 30.00 30.00 36.00 39.00 22.00 16.00 16.00 30.00 Soap0.00 0.00 0.00 0.00 0.00 1.50 1.50 1.50 0.00 STPP 20.00 20.00 20.0020.00 20.00 22.00 22.00 0.00 0.00 Zeolite 12.00 12.00 12.00 12.00 12.0012.00 12.00 34.00 32.00 Sodium Carbonate 33.20 34.10 30.20 26.75 23.6034.80 38.65 38.65 33.70 Sodium Sulfate* 0.50 0.50 3.00 0.55 0.60 0.500.45 0.45 0.50 Acrylic Acid-Maleic 0.50 0.50 0.50 0.50 0.50 0.00 0.000.00 0.50 Acid Copolymer Nonionic Surfactant 0.00 0.00 0.50 0.00 0.004.00 7.00 7.00 0.00 Fluorescer 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.300.30 Enzyme 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 Perfume 0.200.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 Water 2.80 1.90 2.80 3.20 3.302.20 1.40 1.40 2.30 Sodium Sulfate** 0.54 n.t. n.t. n.t. n.t. 0.34 n.t.n.t. 0.50 Remarks *: Amount calculated from starting materialcomposition. **: Amount chemically determined by ion chromatography.n.t.: Not tested.

As is clear from the results in Tables 5 to 10, by dry-neutralizing theliquid acid precursor in the presence of a given amount of an inorganicacid, high-bulk density detergent compositions comprising granules withsmall particle sizes can be obtained at high yields in Examples 11 to22. Also, as is clear from Examples 18 to 21, according to the method ofthe present invention, the desired effects can be exhibited withoutbeing limited to the detergent compositions, and the method isparticularly suitably applicable in the production of phosphorus-freedetergents. Particularly in the case of Examples 11 to 13, it is foundthat as the molar ratio of the inorganic acid to the liquid acidprecursor increases, the particle size of the resulting detergentgranules become smaller, so that the detergent granules with a desiredparticle size can be obtained by controlling the above molar ratio.

On the other hand, in the case of Comparative Example 11 where theamount of the inorganic acid at neutralization is small, the resultinggranules are large, having lower percentages of particles with 1400μm-pass and larger average particle size. Also, in the case ofComparative Example 13 where pulverized sodium sulfate is added, theresulting detergent granules have large particle sizes, so that similareffects to those attained by addition of sulfuric acid cannot beobtained.

By comparing the results of Example 16 with those of Comparative Example14 and the results of Example 17 with those of Comparative Example 15,even more remarkable differences in the percentages of particles with1400 μm-pass and the average particle sizes can be observed in caseswhere the anionic surfactant (LAS-Na) is contained in the resultingdetergent composition in high concentrations. Therefore, the method ofthe present invention is suitably applicable in cases where theconcentrations of the anionic surfactant in the detergent compositionare high.

Also, when comparing the results of Example 18 with those of ComparativeExample 16, in the case where the concentration of the anionicsurfactant (LAS-Na) is low, the microporous surface areas of thedetergent composition increase by addition of the inorganic acid, sothat large amounts of the liquid starting material, such as nonionicsurfactants, can be formulated while maintaining a small particle sizein the detergent granules.

Also, the detergent compositions obtained in each of Examples 11 to 21are subjected to X-ray diffraction analysis, but no diffraction peaksascribed to inorganic salts, such as sodium sulfate, are detectable.

INDUSTRIAL APPLICABILITY

By neutralizing the liquid acid precursor of a non-soap, anionicsurfactant with a water-soluble, solid, alkali inorganic substance inthe presence of a given amount of the organic acid, high-bulk densitydetergent compositions comprising granules having small particle sizescan be obtained at high yields.

1. A method for producing detergent granules, comprising the step ofdry-neutralizing a liquid acid precursor of a non-soap, anionicsurfactant prepared by a SO₃ gas sulfonation method, with awater-soluble, solid, alkali inorganic substance, wherein adry-neutralizing step is carried out in the presence of 0.1 to 1.0 moleof a sulfuric acid per mole of said liquid acid precursor of a non-soap,anionic surfactant; wherein the amount of sulfuric acid preexisting inthe liquid acid precursor of a non-soap, anionic surfactant is 0.05 moleor less per mole of said liquid acid precursor; wherein the sulfuricacid and the liquid acid precursor of a non-soap, anionic surfactant areadded separately to the starting material components; and wherein theresulting detergent granules contain the non-soap, anionic surfactant inan amount of 28% by weight or more and less than 50% by weight, and havea molar ratio of (inorganic salt undetectable by x-ray diffractionmethod)/(non-soap, anionic surfactant) of from 0.1 to 1.0, and theinorganic salt undetectable by x-ray diffraction method is sodiumsulfate.
 2. A method for producing detergent granules, comprising thestep of dry-neutralizing a liquid acid precursor of a non-soap, anionicsurfactant prepared by a SO₃ gas sulfonation method, with awater-soluble, solid, alkali inorganic substance, wherein adry-neutralizing step is carried out in the presence of 0.3 to 1.0 moleof a sulfuric acid per mole of said liquid acid precursor of a non-soap,anionic surfactant; wherein the amount of sulfuric acid preexisting inthe liquid acid precursor of a non-soap, anionic surfactant is 0.05 moleor less per mole of said liquid acid precursor; wherein the sulfuricacid and the liquid acid precursor of a non-soap, anionic surfactant areadded separately to the starting material components; and wherein theresulting detergent granules contain the non-soap, anionic surfactant inan amount of 10% by weight or more and less than 28% by weight, and havea molar ratio of (inorganic salt undetectable by x-ray diffractionmethod)/(non-soap, anionic surfactant) of from 0.3 to 1.0, and theinorganic salt undetectable by x-ray diffraction method is sodiumsulfate.
 3. The method according to claim 1 or 2, further comprising thestep of adding a free-flowing aid after the dry-neutralizing step, tosurface modify the detergent granules.
 4. The method according to claim1 or 2, further comprising the step of adding a liquid component afterthe dry-neutralizing step.
 5. The method according to claim 4, furthercomprising the step of adding a free-flowing aid after the step ofadding a liquid component, to surface-modify the detergent granules. 6.The method according to claim 1 or 2, wherein said liquid acid precursorof a non-soap, anionic surfactant is a linear alkylbenzenesulfonic acidobtained by a SO₃ gas sulfonation method.
 7. The method according toclaim 1, wherein the dry-neutralizing step is carried out in thepresence of 0.3 to 0.8 mole of said sulfuric acid per mold mole of saidliquid acid precursor of a non-soap, anionic surfactant.
 8. The methodaccording to claim 1, wherein the dry-neutralizing step is carried outin the presence of 0.35 to 0.7 mole of said sulfuric acid per mole ofsaid liquid acid precursor of a non-soap, anionic surfactant.
 9. Themethod according to claim 2, wherein the dry-neutralizing step iscarried out in the presence of 0.3 to 0.8 mole of said sulfuric acid permole of said liquid acid precursor of a non-soap, anionic surfactant.10. The method according to claim 2, wherein the dry-neutralizing stepis carried out in the presence of 0.35 to 0.7 mole of said sulfuric acidper mole of said liquid acid precursor of a non-soap, anionicsurfactant.